9 Big Food Product Properties that Show If You’re Ready to Move from Rigid to Flexible Packaging

May 29, 2018 | By Ray Carroll

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As you make the switch to flexible from rigid packaging of your food products, it’s important to have a comprehensive knowledge of their unique properties.

This information will help shape the design of your packaging system, including the filling process, the filling system, and the package itself. It’s important to start by knowing your product’s physical characteristics by asking these nine questions.

1. Is the product dry, liquid or a combination? If it’s dry, is it in pieces like nuts? Or is the product dusty, as with flour or powdered sugar? (Instead of dry, our product may also be liquid, such as a beverage, broth, or sauce. It may even be multiphase, which is a combination of dry and solid food parts combined, such as a soup or a stew.)

2. What is the bulk density or specific gravity of your product? Specific gravity is the ratio of the density of that product compared to the density of another known substance, such as water. This information helps determine the size and strength of the package.

3. How big are the particles in the product? This information will help packagers determine the size of the equipment’s components, such as piping and valves. This information is also pertinent to the design of the package itself. For example, if the particles are small enough, they may become trapped in the package’s seals, compromising them.

4. How sensitive to damage are the particulates during processing? If the particles are delicate enough to be damaged in the course of the filling and packaging processes, or if they are highly concentrated, these factors may require additional considerations in the system design. If they are very sensitive, a possible solution could be to combine them in the final package separately. In addition, packagers need to understand whether these particles will remain suspended in the carrier fluid during the filling process or if the particles need to be handled separately. No one wants to open a package of chicken noodle soup and find that there’s no chicken in it because those chunks were floating at the top of the feed tank when the filling process started.

5. What is the viscosity of the liquid? The consistency or thickness of the liquid will determine how it flows through the filling system, and that could determine the size of the pumps and piping in the system.

6. What is the temperature of the product at time of filling? This information is important for determining the package’s structure. The product may need to be hot in order to increase the product’s viscosity (mentioned earlier) in order to keep it flowing. The product may also need to be hot to activate a starch, which would keep the particles in suspension.

7. What is the product’s chemistry? For example, what is its pH? Is it high- or low-acid? Is it a VOC (volatile organic compound)? A product that’s highly acidic or caustic may react negatively to some packaging materials, so the package’s structure would have to be designed specifically for that situation. Also note that if a food is low-acid (pH>6) and shelf stable (non-refrigerated), you need to comply with FDA or USDA regulations.

8. Is the product sensitive to oxygen, light or moisture? These three conditions may be detrimental to a product. The packaging structure can be designed to protect against these factors.

9. Conversely, do any of your product’s components outgas or leach? If a product leaches gas that may cause expansion, it will damage the seal and compromise the package’s barrier quality. (In a notable example, Fres-co introduced the one-way valve to the coffee market to alleviate the CO2 that roasted coffee exudes. This capability changed the coffee packaging industry.)

There can be other properties in your food products to consider as you make the move from rigid to flexible packaging, and we can cover them in future blog posts. But these nine listed above comprise a comprehensive start to building the best packaging system for your products.

Ray Carroll is a seasoned food and beverage executive with more than 35 years of experience in research & development, food process engineering, and quality. His numerous accomplishments, both domestically and globally, have included the development and implementation of new processing technologies, the creation and launch of new, unique products, management of pilot plant operations, and food safety.